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Presentation on theme: "Fishes."— Presentation transcript:

1 Fishes

2 Common Characteristics
Bilateral Symmetry Fins Gills to breathe Endoskeleton with backbone

3 3 Classes Agnatha ~60+ species Chondrichthyes ~850 species
Osteichthyes ~20,000+ species

4 Agnatha - Jawless Fish

5 Agnatha - Jawless Fish No Jaw Long bodies No scales Cartilage skeleton
One fleshy fin No swim bladder

6 Agnatha: Hagfish Scavenger Feed on dead/dying fish (or whales!)
Drill hole and suck blood and flesh Tentacles for sensory, use tongue to scrape off pieces of flesh on dead fish, can tie themselves in knots hagfish

7 Tie knot at tail, then slide it forward, can revove excess slime, escape from pred. gain leverage when tearing flesh from prey

8 Agnatha: Lamprey Many parasitic Attach with sucker-like mouth
Teeth scrape flesh or suck blood Attach to fish, sometimes whales. Rasp hole in victim with tongue suck out blood and body tissues, rarely kill victims, leave weak and wounded

9 Chondrichthyes - Cartilaginous fish

10 Chondrichthyes - Cartilaginous fish
Sharks, skates, and rays Well-developed fins(paired) Cartilage skeleton No swim bladder Eat anything (almost) Sharp teeth 6-20 rows typical shark has ~3,000 teeth), may go through as many as 24,000 teeth in a lifetime, Don’t breed until years, give birth every other year #’s dwindling snagged for sport, slaughtered for meat, fins,

11 Chondrichthyes - Cartilaginous fish
Skates and rays Mouth on underside Flap “wings” May have sharp spines with poison glands on tail Some generate electricity Search for mollusks and crustaceans, spines for defense, electricity for killing prey or pred “wings are pectoral fins,flap

12 Tiny, toothlike scales called denticles or
placoid scales on sharks

13 Osteichthyes - Bony Fish

14 Osteichthyes - Bony Fish
Endoskeleton of bone Scales - Ctenoid Swim bladder Gill covers - Operculum

15 Osteichthyes - Bony Fish
3 groups 1. Lobe-finned (7 living sp.) 2. Lung fish - gills and lungs to gulp air 3. Ray-finned - diverse Coelacanththought to be extinct found one in 1938 heavy jaws, limblike fins, extra lobe in tail Lungfish, gulp air into modified lung when pools dry up Ray finned thin bony spines called rays are connected by thin skin --->fins ,includes flat bottom dwellers halibut sea horses

16 Shape and Movement Pelvic and Pectoral- stablizers for turning, stopping Dorsal - stablize fish so doesn’t flip Caudal - main thrust for swimming Caudal fin shipped from side to side creates forward thrust, lampreys wriggle like eels, Sharks have stiff fins, powerful swimmers, high speeds, but can’t go backwards or stop fast, no graceful movements, require forward motion to keep from sinking, no swim bladder, have oil in liver to help float. Like airplane


18 Bony fish have flexible fins! Speed and grace, can stop,
Ex. The butterfly fish has great dexterity and maneuverability

19 Swim Bladder in bony fish
Gas-filled sac for bouyancy move easeir and more effeciently, except deep-sea and active swimmers - just keep swimmiong mackeral

20 Coloration Chromatophores (pigments)
Mirror-like silver - light reflecting crystals Countershading in open ocean euphotic Counterillumination

21 Coloration Disruptive Vertical lines, eyespot make it hard to see head

22 Coloration Camouflage Colorful
Colorful for communication for mating or territory or warning toxic or spiny

23 Respiration Blood flows in the opposite direction from water, can exchange gases the whole length of the blood vessel,

24 Respiration Gills extract oxygen and eliminate CO2
Lots of surface area- gill filaments SA from gill filaments to exchange more gases


26 Water flows in the opposite direction from water, can exchange gases the whole length of the blood vessel

27 Respiration Water must flow continously past gills
Bony fish: operculum Sharks : water enters through mouth or spiracle Water must continuously move past gills to keep blood oxygenated Pump water over them like goldfish gulping or swim fast with mouth open Bony fish operculum , water expelled thru single opening on each side of ehad Sharks, no perculum water enters mouth or spiracles on top of body. Passes thru slits on sides of body

28 Excretory system - osmoregulation

29 Some water, CO2 and salt excreted through gills
Kidneys remove wastes and salts

30 Bony fish: Drink saltwater Gills remove salt Don’t pee much(very salty) Sharks: Blood salts similar to sea Water Retain a lot of nitrogenous Waste (urea) Gills and kidneys excrete salt

31 Circulatory system: Closed, 2 chambered heart
No O2 blood from body ->atrium ->ventricle->gills to Get O2 ->body O2 used->back to heart Humans: Body to heart to lungs back to heart to body


33 Nervous System Brain, spinal cord, excellent sense organs Large eyes
Taste and smell: big olfactory sacs with receptors on head and entire body Ears: don’t hear well, but have Lateral line system

34 Nervous system

35 Pores connect to fluid-filled
canals under skin Sensitive to vibrations and pressure waves Detect prey, danger, swim in schools, dark murky water


37 Digestive System Complete digestive tract
Carnivores, herbivores, scavengers, parasites, filter feeders, go fishin’ Shark swallow food whole, have a spiral valve to digest and absorb nutrients instead of intestines

38 Digestive system


40 Reproduction







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